Recently, with the development of electronic industries and the advance of industrial technologies, various electronic devices with optical functions, particularly image capturing, are designed toward small size, light weightiness and easy portability. Consequently, these electronic devices can be applied to mobile business, entertainment or leisure purposes whenever or wherever the users are. For example, various imaging devices are widely used in many kinds of fields such as smart phones, wearable electronic devices, aerial imaging devices or any other appropriate electronic devices. Since the imaging devices are small and portable, the users can take the imaging devices to capture images and store the images according to the users' requirements. Alternatively, the images can be uploaded to the internet through mobile networks. In other words, these electronic devices not only have important commercial values but also provide more colorful lives to people.
With the improvement of the living quality, people's demands on more functions of the imaging devices are gradually increased. For example, many people are willing to acquire the distance information from the captured images or even judge the surface flatness information about the objects of the images. The distance information and the surface flatness information, which are basic elements of spatial three-dimensional structures, are important to some applications of profile identification and reconstruction, so as to advanced control, e.g., the landing control of the aerial imaging devices and collision avoidance of the unmanned aerial vehicles (UAV).
Generally, the current aerial imaging device is equipped with a laser distance detector to measure the distance of the surface to be landed. According to the distance measured by the laser distance detector, the landing process of the aerial imaging device is correspondingly controlled. However, a single laser distance detector is only able to acquire a single distance information (i.e., a single distance information about one point of the surface to be landed). For increasing the landing performance, it is necessary to provide plural laser distance detectors on the aerial imaging device. The plural laser distance detectors can be used to acquire the distances between the aerial imaging device and plural points of the surface to be landed and judge the flatness of the surface to be landed. Under this circumstance, the fabricating cost of the aerial imaging device and the computational complexity are increased.
Based on the above discussions, the conventional method of measuring the distance information and the surface flatness and the electronic device using the method need to be further improved.